From acb4a6bfc80ddeea4c44074dd630f916259e909e Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Tue, 6 Oct 2015 14:49:58 -0700
Subject: [PATCH] tcp: ensure prior synack rtx behavior with small backlogs
Some applications use a listen() backlog of 1.
Prior kernels were silently enforcing a qlen_log of 4, so that we were
sending up to /proc/sys/net/ipv4/tcp_synack_retries SYNACK messages.
Fixes: ef547f2ac16b ("tcp: remove max_qlen_log")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/ipv4/inet_connection_sock.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index 89eedfbd4ad53..514b9e910bd4e 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -579,7 +579,7 @@ static void reqsk_timer_handler(unsigned long data)
* ones are about to clog our table.
*/
qlen = reqsk_queue_len(queue);
- if ((qlen << 1) > sk_listener->sk_max_ack_backlog) {
+ if ((qlen << 1) > max(8U, sk_listener->sk_max_ack_backlog)) {
int young = reqsk_queue_len_young(queue) << 1;
while (thresh > 2) {
--
2.49.0